Check Isomorphic Strings

Problem

Given two strings str1 and str2, return true if they are isomorphic.

Two strings are isomorphic if the characters in str1 can be replaced to get str2, ensuring that no two characters map to the same character and each character maps to itself.

Examples

areIsomorphic("bad", "tog")
// returns true
// Why? Each letter from 'bad' can be reshaped to form 'tog'.

areIsomorphic("cat", "car")
// returns true
// Why? 't' can be changed to 'r' and create an isomorphic sand.

areIsomorphic("ball", "teet")
// returns false
// Why? Letters in 'ball' cannot be reshaped to form 'teet'.